Improved method of heat



UNITED ,STATES PATENT rEicE.

FRANCIS B. STEVENS, OF NEV YORK, N. Y.

n IMPROVED METHOD 0F HEATING FEED-WATER FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 35,7 ht, dated June 24, 1862.

To @ZZ zuwm it may concern:

Be it known that l, FEANoIs B. STEVENS, of

,the city, county, and State of New York, have invented a new and useful Improvement in Heating the Feed-Water of StcanrBoilers, and I do hereby declare that the following is a full, clear, and exact description thereof.

My improvement relates to those steam-engines in which the feed-water is heated by steam taken from the induction side of the pistion; and my object is to improve this method, first, by using only one additional eductionvalve instead of two 5 secondly, by simplifying the machinery that opens and closes this additional valve; thirdly, by rendering the action of the pumps more certain.

When I use only one additional eductionvalve I place it on the cylinder midway between the top and bottom, so that the piston passes the port of this valve in the course of each stroke, and as this valve is never required to open until the piston has performed more than one-half of its stroke it can thus be made4 to serve as the additional eduction-valve for both strokes. A port or nozzle made in the usual manner and placed at the Vcenter of the length of the cylinder would 'be apt to weaken the cylinder too much. Therefore I form the nozzle or port leading from this eduetion-valve to the cylinder by a series of small holesround, oblong, or rectangular. The size of those holes in a vertical direction should be at least half an inch less than the width of the narrowest packing-ring used. By this means I get the requisite opening of port without unduly impairing the strength of the cylinder.

I simplify the machinery that opens and closes the additional valve by placing a tappet on the eccentric-rod that works the main valves, for I have found that in most steamengines when the eccentric that works the main valves is midway in its throw, then the piston is not far from the end of its stroke, being at the position at which the additional eduetion-valve should be wide open. Taking advantage of this fact, I place a tappet on the eccentricrod in such manner that it opens the additional eduction-valve to its full extent when the eccentric opening the main valves is midway in its stroke or throw. It will thus open and close the additional eductionvalve twice while the engine makes one revolution. I render the action of the pump more certain by preventing the water rising too high in the heater whenever any accident may happen to the withdrawing-pump while the injectionpump continues to act. I accomplish this by placing a diaphragm across the heater near its top. I placca valve equal in area to the additional eduction-valve on the lower side of this diaphragm. I balance this valve by means of a lever, a iloat, and a weight. A cup always remaining full of water can be used for a float. This iioat or cup is counterbalanced by the weight attached to the other end of the lever in such manner that when the water rises beyond a certain limit in the lower part ofthe heater it causes the iioat or cup and valve to rise and close the opening in the diaphragm. I make the steam pass from the cylinder into the heater above the diaphragm, and I place the pipes leading to the injection and withdrawing pumps below the diaphragm. Thus this valve will never act while the withdrawing-pump is in order; but whenever the withdrawing-pump ceases its action, then the cup will close the valve in the diaphragm, and the injection-pump, after having filled the heater below the diaphragm, will then force the water through the heater and through the valves of the withdrawing-pump into the boiler.

Instead of using a tappet similar tc those placed on the old-fashioned plug-tree, a much smoother motion can be obtained by making the eccentric-rod work an arm, which, by its Vibration, works a toe or tappet placed on a shaft by a motion withontjar.

Figure I is a side elevation showing the single additional eduction-valve attached to the middle of the cylinder, the eccentric-rod, and the machinery that opens and closes the additional eduction-valve, and also showing heater. Fig. II is a horizontal view of the the diaphragm, the cup, and the weight in the same.

A is the cylinder of the engine. (Shown on Fig. II in section taken through the red or dotted line x x in Fig. I.)

Bis the upper port 0f the cylinder. C is the lower port.

a a are small round holes forming the port of the additional eduction-valve.

D is the Valve-chest of the additional eduction-valve. (Shown in section in Fig. I taken through the red or dotted line y y of Fig. II.)

E is the additional eduction valve, also shown in section in Fig. I. This valve is here represented by a double-beat Cornish puppet-valve, although a single valve properly weighted would answer, or a slide-valve could be used; but it should, after being opened by the tappet, be brought back by a spring or weight in the same manner that the additional expansion-valve is operated in many marine engines. The aggregate openings of the small ports a a must ofcourse be equal tothe opening of the valve.

F is the lifting-rod that lifts the valve E.

G is the main shaft of the engine.v

H is the main crank of the engine.

I is a dial showing the number of degrees that the crank moves.

K is the eccentric wheel that Works the main 4 ing against the lifting-rod, and thus'opening the additional eduction-valve.

P is the eccentric hook that works the main valve of the engine. When this eccentric hook is unhooked, it also unhooks the small hook N, and thus the additional eductionvalve is thrown out of gear whenever the main valve is.

c is the heater. (Shown in Fig. I in section.)

d is the diaphragm.

e is the valve placed in the diaphragm.

f is the lever. f

g is the cup.

lo is the weight.

i' isthe pipe of the injection-pump.

k is the pipe of the withdrawing-pump.

Z is the pipe leading from the cylinder.

The crank H is shown by the dial forty degrecs from the end of its stroke, the piston being then near the bottom of its stroke. The additional eduction-valve F is shown wide open, having been raised from its seat by the tappet O, placed on the bar M and worked by the eccentric-rod L, which is represented midway in its throw. rlhe tappetO is so proportioned that it will lower the valve before the piston gets to the bottom of its stroke. When the valve is Wide open, as shown by the drawings, the steam from the induction side of the piston can pass through the small holes a a and through the` valve E into the heater.

On the return-stroke of the piston, after it has passed the small holes a a, and when near the bottom of the cylinder, the tappet O will again on its return raise the valve E and again allow the steam from the induction side of the piston to enter the heater.

If the cup g in the heater be counter-balanced by the weight h, so that when empty the weight will force it to close the valve e, and when full that it will be heavier than the Weight and will open the Valve, then When 1n operation, the cup being always filled With water, it will keep the valve open as long as the heater is nearly empty; but when the water rises in the heater, then it is evident that the cup will also rise and close the valve e. I place the injection-pipe i directly over the cup to render it certain that the cup shall always l ing toe or tappet. Fig. IV is a cross-section of Fig. III, taken through the red or dotted line z z of Fig. III. Fig. V is a cross-section of Fig. III, taken through the red or dotted line w fw of Fig. III.

Q is an arm that receives its motion4 from the main eccentric-rod by means of the small hook N.

R is the arm of the shaft on which the vibrating tappet S is placed.

'I is a small connecting-rod connecting the two arms Q and R. b b are small pins placed on the small eccentric hook N, to prevent the tappet S from falling too low when the hook N is thrown out of gear.

The arm Q is shown connected to the arm R in such manner that the arm R is at the end of its vibration While the arm Q is inthe center of its arc of vibration, and thus the arm R makes two vibrations While the arm Q makes but one. Thus when the arm Q is in the position shown by the dotted line Q', then the toe or tappet S is depressed to its greatest extent, as shown in S' by red or dotted lines. When the arm Q passes from the position Q to the center of its arc of vibration, the tappet S is then at its greatest elevation, as shown by the full lines in the drawings, and the valve is then wide open. Y When the arm Q arrives at the position Q2, then the tappet S is again at S-its point of greatest depression-the tappet S being thus at the point of its greatest depression, (shown in dotted lines at S,) when the arm Q is both. at the point Q and atthe point Q2'.

What I claim as my invention is- 1. The additional eduction-valve communicating with the cylinder of a steam-engine by an aperture placed at or near the middle of the length of the cylinder, in combination with apparatus-for heating the feed-water of steamengines by steam withdrawn from the induction side of the piston, substantially as shown and described.

2. Forming the aperture or nozzle last named bya number of smallholes,a aa, pierced through the middle of the cylinders, substantially as shown and described. 3. Opening and closing the additional eduction-valve when placed in the middle of the tion with apparatus for heating the feed-Water cylinder by a motion derived from the eccenof steam-engines bysteamwithdrawn from the tric that works the main valves of the engine, induction side of the piston. substantially as shown and described. FRANCIS B. STEVENS.

4. The diaphragm in 'the Closed heater and Vitnesses: the valve attached to the cup, or its equiva- ALBERT S. EAsUM, lent, and balanced by the Weight, in combina- RT. A. ADAMS. 

